Vehicle wheel brake



April 18, 1939. R. FIKE VEHICLE WHEEL BRAKE 2 Sheets-Sheet 1 Filed June 21, 1938 A ttorneys April 18, 1939. R. FIKE VEHICLE WHEEL BRAKE 2 Sheets-Sheet 2 Filed June 21, 1958 y w m f 7% M m a v////// //////Aw In venfor A iiomeys Patented Apr. 18, 1939 UNITED STATES PATENT OFFICE Applicatioi; 21:23.1, 8S8e:ls)No. 214;!)80

15 Figures 2 and 3 are sectional views taken substantially on the lines 2-2 and 3-4 respectively of Figure 1,

Figure 4 is an elevational view of the backin plate, 20 Figure 5 is a perspective view of an adjusting cam, and

Figure 6 is a perspective view of a spreader cam.

Referring to the drawings by reference nu- 25 merals it will be seen that 5 indicates generally a rotatable drum forming part of the wheel brake and 6 indicates the fixed backing plate that, as is well-known, is arranged at the open side of the drum. The brake shoes are indicated by the 30 reference numerals l and are provided with the usual linings 8.

In accordance with the present invention the shoes 1-1 at one end are pivoted to each other and to the backing plate 8 through the medium 35 of a pivot bolt 8 that is accommodated within a slot It provided therefor in thelower portion of the backing plate 6.

Arranged between the confronting or adjacent free ends of the shoes I is a spreader cam III. 40 In the present instance the spreader cam l comprises two sections I I, I2 placed in facial contact and welded or otherwise secured together whereby to provide a cam of a thickness corresponding substantially to the thickness of'the 45 shoes I as will be clear from a study of Figure 2.

The cam I0 pivots on a bolt l3 that extends into the drum through a slot It provided therefor in the backing plate 6.

The cam Ill is retained on the pivot bolt I3 50 between washers l5 and I6, washer l6 being disposed between one side of the cam and a cotter pin or other retaining element ll provided on the inner end of the bolt l3; while washer I5 is interposed between the opposite side of the cam l0 and 55 the backing plate 8. On the outer end thereof the bolt I3 is provided with a nut I8 and a locking washer l9 through the medium of which the bolt I3 is secured at the desired position of adjustment within the aforementioned slot II.

The part or section l2 of cam Hi is provided 5 with an integral lever 20 as shown.

Also, suitably mounted on the backing plate 6 within the confines of the drum 5 is a hydraulic cylinder 2|. Cylinder 2|, as is conventional, has working therein a piston the rod of which is indilo cated by the reference numeral 22 and is pivoted at its outer end as at 28 to the lever 20. Cylinder 2| at one end thereof is connected through the medium of a conduit 24 and in a conventional manner with the usual master cylinder of the hydraulic brake system.

Also, and as shown, lever at the free end thereof is provided with a hook 25 with which is engaged one end of a spring 28, the opposite end of the spring being engaged with a suitable hook 21 mounted on the cylinder 2 1. Obviously, spring 25 acts to yieldably return the piston within the cylinder 2| to its normal position, or the position occupied when the brake is released.

In connection with the above it will be understood that the brake shoes I will be provided with the usual return springs acting to normally retain the shoes out of engagement with the flange of the brake drum.

Also, in accordance with the present invention there is provided an adjusting cam 28. Cam 28 pivots on a bolt 29 that extends inwardly of the brake drum 5 through an opening in the backing plate 6. The cam 28 is retained on the pivot bolt 29 at the desired position of adjustment through the medium of ,a coil spring 38, interposed between the backing plate 6 and one side of the cam 28 and a nut 8| threaded on the inner end of the bolt at the opposite side of the cam. Interposed between the nut 3| and the cam 28 is a lock washer 32 for the nut 3i.

When it is desired to equalize the shoes the cam 28 is adjusted to a point where it will engage the member 20 and cause the cam Ill to expand the shoes to a point where the shoes will lightly engage the drum. Then the-nuts of bolts 8 and I3 are loosened to permit said bolts to slide in the slots l8 and ll of the backing plate 6, which they will do if the shoes are not equalized and then' the nuts are tightened to hold said bolts 9 and I3 in adjusted position. Then the cam 28 is moved back to inoperative position and out of the way of the lever 20 which, of course, will free the shoes from the drum. Thus the cam 28 facilitates the proper adjustment of the two shoes to equalize the pressure of the shoes on the drum when the brakes are applied.

It is thought that a clear understanding of the construction, operation, utility and advantages of a hydraulic vehicle wheel brake embodying the features of the present invention will be had without a more detailed description.

Having thus described the invention what is claimed as new is:

A brake of the class described comprising a backing plate having a pair of slots therein, a pair of shoes, a bolt passing through one slot and pivotaily connecting one end of the shoes together, a cam located between the other ends,

of the shoes, a bolt passing through the cam into the other slot, a lever connected with the cam, actuating means connected with the lever for causing the cam to expand the shoes and a second cam rotatably supported by the backing plate and adapted to be adjusted against the lever to lightly apply the shoes, after which the bolts are loosened to permit the bolts to adjust themselves in the slots to equalize the pressure of the shoes on the brake drum, after which the bolts are tightened and the second cam moved out of engagement with the lever.

ROY FIKE. 

